Method for paying for services and/or goods and apparatus for carrying out the method

A method for payment for services and/goods of a type, using a credit balance means that stores an amount M thereon, comprising steps of:

• prior to a purchase of a service and/or goods:
• reading with a data terminal device said amount M from said credit balance means;
• and
• writing with said data terminal device said amount M into a memory of a security module;
• and
• during said purchase:
• determining with said data terminal device a running cost amount K for said service and/or goods;
• and
• storing back with said data terminal device into said credit balance means an amount M.nu., wherein said amount M.nu. is a difference between said amount M and said cost amount K,
• wherein said method comprises steps of:
• a) providing said memory with a first memory area and a second memory area, and
• b) in a first transaction prior to said purchase, said data terminal device subtracting said amount M from said credit balance means, and adding said amount M to said first memory area;
• c) in a second transaction during said purchase, said data terminal device subtracting said amount M.nu. from said first memory area, and adding said amount M.nu. to said credit balance means;
• and
• d) in a third transaction, said data terminal device transferring said cost amount K from said first memory area to said second memory area,
• wherein transactions to said credit balance means from said first memory area are permitted and/or transactions to said credit balance means from said second memory area are prevented by inhibiting means and/or enabling means.

Apparatus for payment for services and/or goods, comprising

• a credit balance means which stores an amount M;
• and
• a data terminal device for:
• prior to a purchase, reading said amount M from said credit balance means;
• during said purchase, determining a running cost amount K for said service and/or goods during said purchase;
• and
• during said purchase, storing back in said credit balance means an amount M.nu. which is the difference between said amount M and said cost amount K,
• wherein said apparatus comprises:
• a security module with a memory, connected to said data terminal device via a communications channel, wherein:
• said memory comprises a first memory area and a second memory area;
• and said data terminal device is operable:
• in a first transaction prior to said purchase, to subtract said amount M from said credit balance means, and to add said amount M to said first memory area;
• in a second transaction during said purchase, to subtract said amount M.nu. from said first memory area, and to add said amount M.nu. to said credit balance means;
• and
• in a third transaction, to transfer said cost amount K from said first memory area to said second memory area.

Apparatus for payment for services and/or goods, comprising

• a credit balance means provided with an amount M;
• and
• a data terminal device for:
• prior to a purchase, reading said amount M from said credit balance means;
• during said purchase, determining a running cost amount K for said service and/or goods during said purchase;
• and
• during said purchase, storing back in said credit balance means an amount M.nu. which is the difference between said amount M and said cost amount K,
• wherein said apparatus comprises:
• a security module with a memory, connected to said data terminal device via a communications channel, wherein:
• said memory comprises a first memory area and a second memory area;
• and said data terminal device is operable:
• in a first transaction prior to said purchase, to subtract said amount M from said credit balance means, and to add said amount M to said first memory area;
• in a second transaction during said purchase, to subtract said amount M.nu. from said first memory area, and to add said amount M.nu. to said credit balance means;
• and
• to transfer said cost amount K from said first memory area to said second memory area,
• wherein an inhibiting means and/or enabling means is provided for permitting a transaction to said credit balance means from said first memory area and for preventing a transaction to said credit balance means from said second memory area.